Mechanisms of resource acquisition by plant mutualists: multiple host benefits from arbuscular mycorrhizal fungi?

Background: Arbuscular mycorrhizal (AM) associations are ubiquitous occurring on c. two-thirds of plant species. AM fungi (AMF) are central to the phosphorus cycle, transferring P to their hosts; they were considered to be a minor component in the nitrogen cycle, but this has recently been completely re-evaluated (Hodge & Fitter 2010). By changing the nutrient status of their host, AMF potentially alter the vulnerability of plants to herbivores, but the effect is variable with positive, neutral and negative interactions between colonisation and herbivory reported. This variation may be due to different AMF species benefitting their hosts to varying degrees, both in terms of nutrient acquisition and protection against herbivory, but the mechanisms underpinning these are unknown. We will address this knowledge gap by examining the impact of different AMF species on host nutrient acquisition and its chemical composition and the hosts vulnerability to herbivores.

Objectives: To determine

If AMF species differ in their ability to protect plants from herbivory.
How herbivory on the host, and on the AMF, influences N and P acquisition by different AMF.
The chemical mechanisms responsible for these effects.


Novelty: The project takes a multi-disciplinary mechanistic approach to understand multi-trophic interactions of both fundamental and applied importance. It uses novel microcosm-based experimental systems which allow the direct effects of AMF on the host plant to be determined.

Timeliness: The outputs of this project will have far reaching implications for sustainable agriculture. Inputs need to be reduced due to cost of inorganic fertilisers and there declining availability. Key crops (e.g. maize) support high levels of mycorrhizal colonisation which could be exploited to sustain yield. Additional benefits in terms of enhanced resistance of AMF-colonised hosts to herbivores are also important given pest outbreaks are predicted to increase under future climate change.